Zheng Yan, Hu Jiang, Murphy Patricia A, Alekel D Lee, Franke Warren D, Hendrich Suzanne
Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA.
J Nutr. 2003 Oct;133(10):3110-6. doi: 10.1093/jn/133.10.3110.
The bioavailability of soybean isoflavones varies widely among individuals due to many factors, including activities of gut microflora. To characterize factors that affect fecal isoflavone disappearance phenotype and isoflavone bioavailability in women, 35 Asian and 33 Caucasian women, 18-43 y of age, provided fecal samples for anaerobic incubation with isoflavones in vitro at two times 5 mo apart (Phases I and II). Diet, physical activity and health history were investigated at these times. A single dose of soymilk powder [1.2 mg (4.57 micromol) total isoflavone/kg body] was given to all subjects with breakfast in phase II. Daidzein and genistein from fecal incubations, urine and fecal samples were measured by reverse-phase HPLC. Three significantly different daidzein and two genistein disappearance phenotypes were identified from fecal isoflavone incubations. More Asians than Caucasians were identified within the high daidzein disappearance phenotype. Caucasians and Asians differed significantly in daily intake of red meat (0.3 +/- 0.1 vs. 1.0 +/- 0.1 servings/d), dairy foods (2.9 +/- 0.2 vs. 1.2 +/- 0.2 servings/d) and insoluble dietary fiber (3.6 +/- 0.3 vs. 1.4 +/- 0.3 g). BMI, maximal oxygen uptake (VO(2 max)) and physical activity level were significantly greater in Caucasians than in Asians. Asian subjects of the low genistein disappearance phenotype had more rapid gut transit time (GTT) and greater isoflavone bioavailability as reflected in urinary genistein excretion than did Asians of the high genistein disappearance phenotype (GTT, 40 +/- 8 vs. 63 +/- 5 h; 11.0 +/- 2.7 vs. 4.0 +/- 1.7% of ingested genistein excreted in urine). Caucasians of both genistein disappearance phenotypes had longer GTT than did Asian subjects (84 +/- 5 vs. 56 +/- 6 h) and resembled Asians of the high genistein disappearance phenotype in genistein bioavailability. Relatively rapid GTT coupled with a low fecal isoflavone disappearance phenotype as occurred in Asian but not Caucasian subjects produced greater genistein bioavailability, as reflected in urinary genistein excretion.
由于包括肠道微生物群活性在内的多种因素，大豆异黄酮的生物利用度在个体间差异很大。为了确定影响女性粪便中异黄酮消失表型和异黄酮生物利用度的因素，35名亚洲女性和33名高加索女性，年龄在18 - 43岁之间，在相隔5个月的两个时间点（第一阶段和第二阶段）提供粪便样本用于体外与异黄酮进行厌氧培养。在这些时间点调查了饮食、身体活动和健康史。在第二阶段，所有受试者早餐时服用单剂量豆浆粉[1.2毫克（4.57微摩尔）总异黄酮/千克体重]。通过反相高效液相色谱法测定粪便培养物、尿液和粪便样本中的大豆苷元和染料木黄酮。从粪便异黄酮培养物中鉴定出三种显著不同的大豆苷元消失表型和两种染料木黄酮消失表型。在大豆苷元高消失表型中，亚洲人比高加索人多。高加索人和亚洲人在红肉（0.3±0.1份/天对1.0±0.1份/天）、乳制品（2.9±0.2份/天对1.2±0.2份/天）和不溶性膳食纤维（3.6±0.3克对1.4±0.3克）的每日摄入量上有显著差异。高加索人的体重指数、最大摄氧量（VO₂max）和身体活动水平显著高于亚洲人。低染料木黄酮消失表型的亚洲受试者比高染料木黄酮消失表型的亚洲受试者肠道转运时间（GTT）更快，染料木黄酮生物利用度更高，这体现在尿中染料木黄酮排泄量上（GTT，40±8小时对63±5小时；尿中排泄的摄入染料木黄酮的比例为11.0±2.7%对4.0±1.7%）。两种染料木黄酮消失表型的高加索人的GTT都比亚洲受试者长（84±5小时对56±6小时），并且在染料木黄酮生物利用度方面与高染料木黄酮消失表型的亚洲人相似。如在亚洲受试者而非高加索受试者中出现的相对较快的GTT与低粪便异黄酮消失表型相结合，产生了更高的染料木黄酮生物利用度，这体现在尿中染料木黄酮排泄量上。
